Reverse Engineering: From a Broken Part to a Printable File

A photo shows the shape. It does not give the size. A camera also bends straight lines a little, so nobody can measure from a photo. And a broken part is missing the piece that broke. Photos plus a few caliper readings settle both problems.

There are two ways to fix that: add caliper readings to your photos, or mail us the part.

1. Top, straight down, with a ruler or tape lying next to the part
2. Bottom, straight down, same ruler
3. Each side, straight on
4. A close-up of the break or the worn spot
5. The part in place on the machine, or next to the part it mates with
6. A sharp close-up of any molded part number or date wheel

Use flat, even light. No flash glare. Set the part on a plain background that contrasts with its color, and hold the phone parallel to the part, not tilted. Black shiny plastic is the hardest to shoot. A sheet of white paper underneath and light from the side helps a lot.

Mating sizes

Anything that slides into, snaps onto or presses into something else. Outside of a boss, inside of a bore, width of a tab, depth of a slot. Measure each twice, in two spots.

Hole spacing

Center to center between mounting holes, both directions, plus hole diameter and the distance from a hole to a reference edge.

Shaft and bore

Measure the shaft the part rides on, not the worn hole in the broken part. For a D shaft, the full diameter and the flat-to-round distance.

Thread

Outside diameter, pitch, and whether it is straight or tapered pipe thread. A pitch gauge settles it. Do not guess.

Overall size and thinnest wall

The longest size in each direction decides which production path fits. The thinnest wall decides whether the part prints well.

Which way it faces

Which way the tab points relative to the holes. One photo with an arrow drawn on it is enough.

What it does

Does it spin, slide, get stepped on, hold a spring, get hot, live outside. Only you know this, and it picks the material.

No calipers?

• Buy a digital caliper. It is cheap and pays for itself the first time. Send readings in millimeters to two decimals.
• Mail the part. Better when the part is complex, worn or in pieces.
• For a flat part, trace it on paper with a pen held straight up, mark hole centers with a pencil point, and photograph the paper flat with a ruler in the frame.

1. Submit the request first. We reply with the mailing address and your request number.
2. Put the request number in the box.
3. Send every piece, including broken-off fragments. They carry the shape that is missing from the main body.
4. If the mating part is cheap and spare, send that too, or a photo of the part in place.
5. Bag it, then bubble wrap, then a rigid box. A crushed sample is a lost sample.
6. Write keep or return on the note. If return, the sample comes back after the job ships.

Measuring and modeling a sample is a human job. It gets quoted, not priced instantly.

• Measurement of the sample or caliper photos
• A rebuilt model that matches the mating sizes
• A thicker wall or a rounded corner where the old part broke, if you want it

A model of the part and a printable file.

After that, you approve a model, we print a first part, and we revise it if it does not fit. Once the run is right, the approved file is saved and can be reordered at today's price from your order page.

The design work is quoted by a person as its own line. The print uses our standard per-part pricing.

A printed part cannot carry the original's listing or pressure rating.

• We do not make parts that carry or touch drinking water in a supply system.
• We do not make parts that hold pressure, in water, air, hydraulic fluid or refrigerant.
• We do not make parts that hold, insulate or enclose live electrical connections.
• We do not make machine guards, interlock parts, fall protection, lifting parts, fire door or exit hardware, or anything a person's safety rests on.
• A part that lives in a hot place gets a human review before we quote it, and often a different material.

See the full list on trades and field service.

Most parts print with a 0.4 mm nozzle. Fine detail, small text or thin walls can be reviewed for a 0.2 mm nozzle on our own printers. A person confirms it before you pay.

One-piece parts up to about 220 mm on the longest side price instantly. Up to 250 mm goes through a person. Larger parts are split or quoted.

Your files and your sample are kept private. We sign a mutual NDA on request.

We design and print parts you have the right to make. If a part is someone else's protected design, tell us before we start.